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Author(s):
V.P. Shevelko, H. Tawara and E. Salzborn
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Title:
Multiple-Ionization Cross Sections of Atoms and Positive Ions by Electron Impact
Date of publication:
July 1995
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Key words:
atomic coIIisions, ionization potential, multiple electron ionization, effective cross section
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Abstract:
For the first time, semiempirical formulae for muItipIe-ionization (MI) cross sections sigma_n of atoms and ions by electron impact are suggested for ejection of three or more electrons n geq 3. The formulae have been deduced on the basis of available experimental data on sigma_n and the assumption of the Born-Bethe dependence of sigma_n on the incident electron energy E. A comparison o f the cross section described by the semiempirical formula suggested with experimental data available for neutral atomic targets from Ne up to U and ejection up to 13 electrons and with those for positive ions from Ar^+ up to W^4+ with ejection up to four electrons shows that the formulae can be used for estimation of MI cross sections sigma_n, n leq 3, from threshold up to high electron energies E approx 10^5 eV for an arbitrary atomic or ionic target.
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